Pain and negative emotions: the vicious cycle

In a recent study, Penn State researchers find emotions such as anger or sadness often are the result of stress or pain, and that they could function as stressors themselves.

In the study, the team examined the relationship between emotion and pain among women with rheumatoid arthritis.

They hypothesized that inflammation – a physiological phenomenon for which biomarkers from blood can be obtained – may be connected to emotion and pain.

They also developed a novel methodology and used it to test how emotional state, such as anger, sadness or happiness, affected inflammatory response to a pain stimulus.

The study participants each came for a five-hour visit on four separate occasions to the Clinical Research Center at Penn State.

These visits varied only by the manipulation of emotion (anger, sadness or happiness versus a non-emotional control visit).

To manipulate emotion, the researchers had participants think, write and talk about their recent feelings related to one of these specific emotions.

After the emotional manipulation, the acute pain was caused by pressing on tender or swollen joints of participants, such as what might be done during a routine clinical examination.

Blood samples were then obtained at multiple time points, including at baseline, ten minutes, one hour, and 100 minutes after the pain stimulus.

The team found there was no main effect of experimental condition; however, when participants reported greater anger than their own average, they showed elevated inflammation.

The finding suggests that emotional states can cause or contribute to specific patterns of physiological responses to stress or pain.

People often think of emotion as a consequence of stress or pain, but the study suggests that under certain circumstances, negative emotion or complex, mixed emotion can function as a stressor itself, and one which can promote inflammation.

The work may eventually help develop novel clinical tools to treat inflammation and pain or help improve current pain management techniques.

Jennifer Graham-Engeland, associate professor of biobehavioral health, is the lead author of the manuscript.